FIX: when using arrow to bottom fetch from newest (#22860)

We were attempting to fetch from last read but this is actually complicated to get right when you have a lot unread, as we might still have more to load after this but the last unread id is still the same and would make the user end up in a loop.

plugins/chat/assets/javascripts/discourse/components/chat-channel.js

@@ -427,9 +427,8 @@ export default class ChatChannel extends Component {
   @action
   scrollToLatestMessage() {
     if (this.messagesLoader.canLoadMoreFuture) {
-      this.fetchMessages({ fetch_from_last_read: true });
+      this.fetchMessages();
     } else if (this.messagesManager.messages.length > 0) {
-      this._ignoreNextScroll = true;
       this.scrollToBottom(this.scrollable);
     }
   }